CEMP-E
EI 11C103
1 March 1997
CHAPTER 3
DETERMINATION OF CAPACITY REQUIREMENTS
1. TOTAL STORAGE REQUIREMENTS. The amount of water storage provided will conform to the
requirements set forth herein. Request for waivers to depart from these requirements will be forwarded to
HQDA (DAEN-ECE-G) WASH DC 20314 for Army projects and to HQ USAF/LEEEU WASH DC 20332 for
Air Force projects.
a. All military installations. In general, total storage capacity, including elevated and ground storage,
will be provided in an amount not less than the greatest of the following items.
Item 1: Fifty percent of the average total daily domestic requirements plus all industrial requirements.
This will provide minimum operational storage needed to balance average daily peak demands on the
system and to provide an emergency supply to accommodate essential water needs during minor supply
outages of up to a one-day duration. For the purposes of this item, essential water needs do not include the
fire demand.
Item 2: The fire demand. The fire demand is the required fire flow needed to fight a fire in the facility
(including water required to support fire suppression systems) which constitutes the largest requirement for
any facility served by the water supply system (calculated in accordance with MIL-HDBK-1008B); plus 50
percent of the average domestic demand rate plus any industrial or other demand that cannot be reduced
during a fire period. This amount will be reduced by the amount of water available under emergency
conditions during the period of the fire (MIL-HDBK-1008B). Large and diverse projects where the fire flow is
a major consideration require the services and review of a qualified fire protection engineer.
NOTE
The fire demand quantity must be maintained in storage for fire protection at all
times except following a fire fighting operation when the fire demand quantity
would be depleted. If depleted, the water system must be self-replenishing and
capable of refilling the required volume within 48 hours during normal operation
and within 24 hours when normal consumption is curtailed. It is recognized that
during daily periods of peak consumption due to seasonal demands, the amount
of water in storage will be less than full storage capacity; however, conservation
methods will be instituted to prevent drawdown of water in storage below the fire
demand quantity. Water storage greater than the amount determined by the
largest of Items 1, 2, or 3 may be required because of appropriate adjustments
for emergency water quantity or other applicable factors; however, this must be
substantiated by actual data on a repeated annual basis documenting the low
storage levels occurring during normal peak demand.
Item 3: The sum of Items 1 and 2 above, that is, the sum of fifty percent of the average total daily
domestic requirements, all industrial requirements for an average day which cannot be shut off during
emergency conditions, and the required fire demand. The sum of the above items will be reduced by the
amount of water available in 24 hours under emergency conditions. This will provide maximum storage
where emergency water supply is a minimum over a 24-hour period or a supply main outage would
significantly affect overall supply conditions. The most economical alternative for meeting the water storage
requirements will be selected in all cases. Installation of additional emergency pumping facilities,
additional water supply connections, drilling additional wells or other modifications to the water system
which will be more cost effective than increasing storage capacity will be developed.
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